Control device for alarm mechanism



Oct. 31, 1933. c. P. HOWARD 1,932,783

CONTROL DEVICE FOR ALARM MECHANISM Filed Oct. 2, 1931 o MQQX? lrcdemv"Patented Oct. 31, 1933 CONTROL DEVICE FOR ALARM MECHANISM Clifton P.Howard, Worcester, Mass., assignor to Rockwood Sprinkler Company ofMassachusetts, Worcester, Mass, a corporation of MassachusettsApplication October 2, 1931. Serial No. 566,569

4 Claims. (01. 200-142) This invention relates to mechanism designed tosound an alarm on the occurrence of a rise in temperature of thesurrounding atmosphere above a predetermined point. The invention ispar- 5 ticularly directed to the temperature responsive device by whichthe alarm mechanism is controlled.

It is the object of my invention to provide an improved control devicewhich will occupy very l slight head room and in which all movable andcontact parts are efiectively covered and pro tected.

My invention further relates to arrangements and combinations of partswhich will be herein- 15' after described and more particularly pointedout in the appended claims.

A preferred form of the invention is shown in the drawing, in which Fig.1 is a side elevation of my improved con 0 trol device;

Fig. 2 is a bottom View thereof, looking in the direction of the arrow 2in Fig. 1;

Fig. 3 is a plan view, looking in the direction of the arrow 3 in Fig.1;

Figs. 4 and 5 are sectional side elevations showing the parts indifferent relations;

Fig. 6 is a sectional perspective view of the locking member, and

Fig. 7 is a detail sectional view showing a slight modification.

Referring to the drawing, my improved control device is mounted in acasing 10, preferably of hard rubber or some other non-conductingmaterial. The casing is provided with an extended flange or base 11which may be secured against a supporting structure A by screws 12.

A pair of contact members 14 and 16 are secured in an inner recess ofthe casing in any V convenient manner as by screws 17. The mem- 40 bers14 and 16 are provided with ofiset contact projections 20 and are alsoprovided with binding screws 21 by which wires W may be secured thereto.Two binding screws 21 may be provided for each member 14 or 16, so thatthe devices may be conveniently connected in parallel between pairs ofwires W if so desired.

A U-shaped contact plate 25 (Fig. 3) is secured at its middle portion tothe long arm of a lever 30, pivoted at 31 in the casing 10 and having anotched end portion 32 extending out through a slot or opening 33 in'thecasing. The slot 33 is formed in the side wall of a recess 35 in theouter face of the casing 10, and a small slot 37 (Fig. 5) is formed inthe opposite side wall of the recess 35.

A spring 40 is seated in a pocket 41 in the casing 19 and engages thefree end of the lever 30. When the lever is free to move, the spring 40forces the contact plate 25 against the offset contact projections 29 ofthe members 14 and 16, thus completing the circuit between the wires W.

A locking meinber'M is interposed between the side Wall of the recess 35and the notched end 32 of the lever 30, as clearly shown in Fig. 4. Whenthe locking member M is thus positioned, the spring 40 is compressed andthe contact plate 25 is separated from the contact projections 20, asalso shown in Fig. 4.

The locking member M may be of any suitable heatresponsive construction,but is shown in the drawing as comprising two thrust elements 44 and 45,normally secured together by a low melt ing alloy or solder S by whichthe parts 44 and 45 are sweated together.

The part 44 is provided with an offset end portion 44 The part 45 ispreferably formed of relatively thin sheet material and is provided withan inwardly offset and down-turned end portion 48 and with downwardlyand outwardly flaring wing portions 49. The portions 48 and 49 assist inholding the solder S when the parts are being secured together. Asubstantial portion of solder is disposed between the end of the part 44and the down-turned end 48 of the part 45, thus more firmly securing theparts.

The inner end of the part 45 engages a shoulder 50 on the part 44, sothat the member M forms arigid strut so long as the solder S remainsunmelted. On a rise in temperature above a pre determined point,however, the parts 44 and 45 are released and fly apart, as indicated inFig. 5, thus releasing the lever 30 and allowing the spring 40 to closethe circuit.

The wings 49 not only serve to retain the solder as previouslydescribed, but project downward and outward when the device is in use,as indicated in Figs. 1 and 4, and materially assist in directing anupward current of warm air against the solder, thus making the member Mmore quickly responsive to an excessive rise in temperature.

The details of construction of the locking member are not claimed hereinbut form the subjectmatter of a copending application of Robert H.Russell, Serial No. 499,520, filed December 2, 1930.

.For additional protection of the contact mechanism, I preferablyprovide an interior cover plate secured by screws 61 and affordingprotection for the contact elements during shipment or whenever thedevices are removed from their supporting structure. It is unnecessaryto remove the inner cover when installing the device, as the contactscrews 21 are accessible at the sides or the cover plate.

In Fig. '1 I have indicated a slight modification by which my controldevice may be adapted to closed circuit operation. For this purpose, theends of the contact projections are bent downward so as to be engaged bythe plate 25 when the parts are in normal position but to be separatedwhen the lever 30 is releamd.

It will be evident from inspection of the drawing that my improvedcontrol device is very compact and that it occupies very slight headroom, thus making it particularly well adapted for use on ship-board orin other situations where head room is limited.

Having thus described my invention and the advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claims, but what I claim is:---

l. A control device for an alarm system comprising a casing ofnon-conducting material an inner and an outer recess and having anopening in the partition between said recesses, contact elements securedin said inner recess, a lever movably mounted in said casing and havinga portion projecting through said opening, a movable contact elementmounted on the inner end or said lever, a spring tending to move saidlever and change the relation or said contact elements, and aheat-releasable locking member interposed between a side wall of saidouter recess mu the outer end 01' said lever and normally preuqitingmovement of said lever by said spring.

2.A control device iman alarm system comprising a casing 01non-conducting material hav-- ing an inner and an outer recess andhaving an opening in the partition between said recesses, contactelements secured in said inner recess, a lever movably mounted in saidcasing and having flvol tion projecting through said opening, a movablecontact element mounted on the inner end of said lever, a spring seatedin a pocket in said casing and tending to move said lever and change therelation of said contact elements, and a heat-releasable locking membercomprising a pair of thrust elements normally secured together by a lowmelting solder, said member being interposed between a side wall of saidouter recess and the outer end of said lever and normally preventingmovement of said lever by said spring.

3. A control device for an alarm system comprising a casing having innerand outer recesses, fixed contact elements mounted in said inner recess,a lever pivoted in said inner recess and to which a movable contactelement is secured, said lever having a portion extending into saidouter recess, a spring engaging said lever and tending to move saidlever to change the relation oi said contacts, and a heat-releasablelocking thrust member positioned in the outer recess of said casing andabutting the outer end of said lever to normally hold said lever againstmovement by said spring.

4. A control device for an alarm system comprising a casing having innerand outer recesses, fixed and movable contact elements mounted in saidinner recess, a lever pivoted in said casing and to which said movablecontact element is secured, a spring tending to move said lever tochange the relation of said contacts, and a heatreleasable lockingthrust member positioned in said outer recess of said casing andinterposed between one end of said lever and an opposite side wall ofsaid casing, said trust member being formed of a plurality of partssecured together by low melting solder and normally resisting endwisepressure thereon, said member thereby holdmg said lever against movementby said spring until said thrust member parts are released by themelting of the solder so that the parts thereof may move relatively toshorten said member and to relieve the endwise pressure of said springthereon.

CLIFTON P. HOWARD.

